1. Field
One or more embodiments of the present invention relate to a multi-layered structure for drug reservoir and a drug-eluting stent including the same.
2. Description of the Related Art
Recently, as the population ages, demands of implantable therapeutic devices, such as a vascular stent for coronary artery and peripheral artery, have been increased, and accordingly, imports of these devices are steadily increasing.
However, after surgery, implanted vascular stents may cause, thrombosis-induced acute obliterating, and stents themselves may act as a traumatic factor with respect to endovascular membrane, thereby causing intimal hyperplasia and then restenosis.
Accordingly, together with a surface treatment to suppress thrombosis, functional surface reformation techniques for embodying a drug-eluting function that allows a therapeutic drug to be directly delivered into blood vessels are required.
In response, Hepacoat Company et al. commercialized a stent that is coated with heparin suppressing thrombosis, and Cordis Company produced, as a drug-eluting stent for the suppression of vascular restenosis, Cypher™. However, these stents caused, for example, death of patients who recently received stent implantations. Accordingly, there is a need to develop stents that have improved drug-eluting performance.
Korean Patent Publication No. 2004-0028486 discloses a drug-release antithrombogenic multi-layer coated stent and a method of preparing the same, wherein the stent enables biologically active agents to be carried to provide localized treatment at the implant site. However, a drug-eluting stent including a micelle layer stacked using a phenol derivative, such as tyramine, has not been disclosed.